Optoelectronic properties of arginine-doped tungsten disulfide quantum dots synthesized via microwave heating

Here, the hysteresis and negative photoconductivity (NPC) in arginine-doped tungsten disulfide (WS2) quantum dots (QDs) synthesized via microwave heating method were investigated and discussed. WS₂ solution and arginine were used as the QDs and dopant sources, respectively. The structure of arginine-doped WS₂ QDs was analyzed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The synthesized arginine-doped WS₂ QDs displays a diameter of less than 10 nm and demonstrates an excitation-dependent photoluminescence (PL) behavior. The PL intensity of arginine-doped WS₂ QDs displayed an 18 folds increase compared to the pristine WS₂ QDs. The electrical transport demonstrated a p-type doping as a result of the introduction of arginine in WS₂ QDs. I-V measurements in varying environment and laser illumination were utilized to investigate the hysteresis and negative photoconductivity (NPC) phenomena in arginine-doped WS₂ QDs. Based on this analysis, the hysteresis and NPC are proposed to originate from the interaction of water and/or gas molecules adsorbed on the surface of arginine-doped WS₂ QDs. This optoelectronic study of WS₂ QDs is expected to contribute for the potential development and performance improvement of WS₂-QD-based devices.